Spittlebugs, chinch bugs and sod webworms are common insect pests that may damage lawns in North Florida during mid-summer through fall.
Spittlebugs are fairly common this time of year, particularly in centipedegrass lawns. Spittlebugs are black with two orange stripes across their back. You’ll often see them as you’re mowing the lawn. As spittlebugs feed, grass blades become discolored with cream colored and pinkish-purple stripes running the length of individual blades. The injured grass later turns brown. Don’t worry about a few spittlebugs. But if you see lots of them, you may need to use an insecticide labeled for lawn insect control. Be sure to apply the insecticide in a sufficient enough volume of water to flush it down through the thatch layer where young spittlebugs are developing in masses of spittle.
Chinch bugs only damage St. Augustinegrass. They are usually found in open sunny areas of the yard during the warmer summer weather and into fall, particularly if it’s dry.
Immature chinch bugs are pink to bright red and are about the size of a pinhead. The adults are only 1/8 inch long and black with white wings.
Inspect a St. Augustine lawn weekly during spring, summer and fall. Look for off color areas that quickly turn yellow and then straw brown. Part the grass at the margin of the yellowed areas and closely examine the soil surface and base of the turf for the tiny insects. Another option is to use a Dust Buster or hand-held vacuum cleaner to suck up any chinch bugs near damaged areas. Remove the filter and empty the contents into a flat container. Then spread out the collected debris to make it less likely for chinch bugs to hide and look for the tiny nymphs and adults. Repeat in several damaged areas.
When spraying for chinch bugs, only treat damaged areas and a ten foot or so buffer around them. It’s usually not necessary to treat the entire lawn.
Sod webworms become active this time of year. They feed at night so don’t be surprised if you can’t find them during the day. The greenish or tan caterpillars will be resting, curled up near the soil line. If your lawn has damaged spots, look closely for notched leaf blades. This is the telltale sign of their chewing damage. You may also find a dusty material left behind by the feeding of the caterpillars. Sod webworms can be controlled with the same insecticides as the other lawn insects. But you may use insecticides that contain Bacillus thuringiensis, a bacterium that only kills caterpillars and won’t harm beneficial lawn insects.
Larry Williams, UF/IFAS Extension Agent, Okaloosa County, July 31, 2015